It is unclear if the encephalopathy associated with type II RHM is a secondary consequence of heart failure, but interestingly, it was recently reported that cardiomyocytes require CYB5R3 activity to sustain their mitochondrial homeostasis, and their deficiency in the heart leads to death in mice at 15 days after deficiency induction [41]. The gene discussed is CYB5R3; the disease is Encephalopathy.